As others have said, if it cost you nothing and if you make a
cent, you profit.
This really needs to be born in mind especially if you play via the Freeroll Club in private freerolls with (by definition) smaller fields. These tourneys cannot be valued enough both for the cashes they provide and the experience of playing a higher caliber of player. This is not to claim they are super sophisticated- they are not, but they are a step up in everyone's poker education and some players are very good.
When you start in the FRC (but this
applies broadly to any freeroll) you should give yourself some specific goals. The first to learn to cash regularly. The reason for this is it makes you hyper aware of exactly where you stand throughout the tourney and how to navigate the bubble. Plus, it cannot be underestimated what this does for confidence. If you cash regularly you will develop a sound pre-bubble game and then it will become almost natural for you to open up your range and aggression post bubble. If you cash regularly you give yourself more opportunities to ladder up.
That said, there is an argument to be made to swing for the fences, to try to double up early then take an aggressive stance through the entire tourney attempting to make the final table (with noticeable increases in terms of payouts). Go big or go home. It's a valid point and one which should be employed at least some of the time...but...I think it can develop some bad habits. People play in an overly aggressive manner, broaden their range too much. In short, it's frequently obvious people are playing in a lazy, undisciplined manner. They actually can't be too bothered.
And that brings me back to some basic points if you want to profit from freerolls - as it's been established you can.
Take the freerolls seriously - in fact, if feasible limit your activity over a period to building a bank exclusively from FR's- be determined to do so. Prove to yourself you can win in an environment that is full of aggression because that is going to stand you in good stead elsewhere.
I recently listened to Jason Koon explain how he literally isolated himself and plowed through around 50,000
hands over a period of weeks to improve a specific weak spot in his game. This was in the broader context of perpetually studying and developing his (our!) game.
If you believe you have 'game' and the kind of determination a player like Koons has to succeed, then I believe not just profiting but building a bankroll from strategically playing freerolls is an end to itself. A great exercise to undertake. The flip side being if you do not have the focus and determination to launch yourself at such a project on this level, then you should ask yourself what you believe you can get out of the game in the longer term.
Freerolls are free money. I can't think of many, if any, places outside of poker where the equivalent of freerolls are offered daily. How can anyone -specifically when building a bankroll- not be motivated to take advantage?